When you
receive this event, the structure members are set as
follows.

The type member
is set to the event type constant name that uniquely
identifies it. For example, when the X server reports a
GraphicsExpose event to a client application, it
sends an XGraphicsExposeEvent structure with the type
member set to GraphicsExpose. The display member is
set to a pointer to the display the event was read on. The
send_event member is set to True if the event came
from a SendEvent protocol request. The serial member
is set from the serial number reported in the protocol but
expanded from the 16-bit least-significant bits to a full
32-bit value. The window member is set to the window that is
most useful to toolkit dispatchers.

The window
member is set to the window whose associated property was
changed. The atom member is set to the property’s atom
and indicates which property was changed or desired. The
time member is set to the server time when the property was
changed. The state member is set to indicate whether the
property was changed to a new value or deleted and can be
PropertyNewValue or PropertyDelete. The state
member is set to PropertyNewValue when a property of
the window is changed using XChangeProperty or
XRotateWindowProperties (even when adding zero-length
data using XChangeProperty) and when replacing all or
part of a property with identical data using
XChangeProperty or XRotateWindowProperties.
The state member is set to PropertyDelete when a
property of the window is deleted using
XDeleteProperty or, if the delete argument is
True, XGetWindowProperty.